No one person pushed the limits of ocean sciences further than Sylvia Earle. As the first female chief scientist of the National Oceanic and Atmospheric Administration, Earle has an unparalleled professional resume, but what really sets her apart is the time spent underwater, often in harm’s way, for the sake of science. In 1970 she led a team of “Aquanauts” in the underwater capsule Tektite II, the first in-the-sea science program that explored, among other things, whether saturation diving in an underwater lab was safe for humans (the team lived 50 feet underwater for two weeks). In 1979, at age 44, she walked untethered on the sea floor at a depth of 1,250 feet — lower than any human being before — in a suit of her own design. In the 1980s, soon before becoming the Chief Scientist at NOAA, Earle turned her attention toward constructing undersea vehicles with engineer Graham Hawkes, hoping to open up the ocean to more private exploration. Now 81, Earle continues to dive as a National Geographic Society Explorer-in-Residence and, tellingly, has spent nearly a year of her life — more than 7,000 hours — underwater.

"Never give up" — that was from my parents. My major professor when I was a graduate student said it another way: "Don’t take no for an answer." If it is something you really want to do, find a way to make it happen. Don’t let others discourage you from doing something you really care about.

Where did you get your passion for the ocean?

From the ocean itself. I became acquainted with it when I was about three years old. That is my first memory, on the Jersey shore, the woozy exhilaration of getting tossed around by the waves and finding life — big horseshoe crabs, starfish, seaweed. I found them endlessly fascinating, and still do.

Never having enough hours in the day to do all the things I want to try to do. There are always things I want to do. I wish for more time to explore and understand and communicate what I see, to savor the joy of being alive. Obviously, I can’t do everything. Setting priorities is difficult, there are things out of my control.

What's the hardest thing you’ve done physically?

Operating the JIM underwater suit with just muscle power, no motor. It was designed for those taller and stronger than myself. In 1979, Oceaneering International allowed me to use one. It was the first time it had been used for scientific application and the first time without a tether to the surface. I was 1,250 feet under water with no cable, no one to tell me which way to go, no decompression. That is what led me to seriously work with engineers to build submersibles and deep rover systems that go to 1,000 meters and that don’t require great strength. They are like driving a golf cart. I encourage people to package their intellect rather than be overly concerned about physical strength.

What is the most important part of this planet to conserve?

All of it. To the extent that we can, what remains of the natural world. Think of nature as our life support system, we have to take care of it as if our lives depend on it because, in fact, they do. Sometimes small things have big consequences, and we have only begun to appreciate our impact on the natural world.

What will this planet look like in 1,000 years?

It truly depends on what we do in the next century and particularly the next 10 years. We are at a crossroads. Scientists around the world, including me, are trying to establish some concept of the limits. How much can you take from the ocean, how much carbon and methane can we release into the atmosphere, how much carbon dioxide can we put in the ocean, before we get major shifts we cannot reverse? We have the power to protect and maintain the natural world in ways that will favor us, or to continue what we have been doing in ignorance and forever lose the chance.

You’ve been the first or only woman in a lot of places. What do you wish men knew about that kind of woman?

It’s not a big deal. It is a matter of coming along at a time when it’s been possible to do things that were not possible before. I think society has come to the point where we see beyond physical aspects — color of skin, gender — and embrace and welcome diversity. By no means universally, but as compared to any time or country in the past. Knowledge makes it possible to do things for the first time, not just for women. All of us are participating in this marvelous adventure of understanding where we came from, who we are, and where we might be going.

You don’t eat seafood. Why?

I know too much. It is one thing if you are truly dependent on ocean wildlife for sustenance, and some people are. But most of what is extracted from the ocean is not fulfilling a need, it is fulfilling a choice. If you understand how fish are caught and the real cost of industrial fishing, it will make you lose your appetite. I certainly lost mine. I value fish more alive than on a plate. We have tended to look at wildlife as commodities — sources of food, or fur or decorations. Now we know they have other values.

What scares you?

Ignorance, widespread ignorance. People who either don’t know and therefore don’t care, or do know and still don’t care.

Where is the coolest place you’ve ever been?

The next place, wherever it is. Or almost anywhere, 50 years ago. There are a few places still like they were, the south coast of Cuba, pristine areas in the deep sea, waters around Antarctica. Despite human impact, there are wild places. Those hope spots, places still in pretty good shape that provide reason for hope that we can reverse the decline. Earth is in trouble and we’re in trouble, but it’s not too late.